1. Field of the Invention
The present invention relates to a semiconductor device and a method of testing thereof. In particular, the present invention relates to a TCP (Tape Carrier Package) type semiconductor device and a method of testing thereof.
2. Description of Related Art
A probe card used for testing a semiconductor device is publicly known. The probe card has a large number of probes that come in contact with test terminals of a test target. The test is performed by bringing respective ends of the probes into the corresponding test terminals, supplying a test signal from a tester to the test target through the probe card and retrieving an output signal from the test target. At this time, it is required to correctly bring each probe into one-on-one contact with the corresponding test terminal so as not to cause a short failure and the like.
Meanwhile, a pitch between adjacent test terminals is getting narrower due to recent miniaturization and increase in the number of terminals of the semiconductor device. Therefore, the probe card also needs to follow the narrowing of the test terminal pitch. For example, it may be considered to narrow a pitch between ends of adjacent probes of the probe card following the narrowing of the test terminal pitch. However, there is a limit to the narrowing of the pitch between the probe ends because electrical isolation must be ensured between the adjacent probes. Consequently, it is proposed to distribute positions of the probe ends over a plurality of rows. Due to this configuration, it is possible to narrow a substantive pitch between the probe ends while ensuring the electrical isolation between the probes, which enables following the narrowing of the test terminal pitch. Probe cards having such the probe pattern are disclosed, for example, in Japanese Patent Publication JP-H08-94668A, Japanese Patent Publication JP-H08-222299A and Japanese Utility Model Publication JP-H04-5643A.
Moreover, a TCP (Tape Carrier Package) type semiconductor device is publicly known. In the case of the TCP, a semiconductor chip is mounted on a base film such as a TAB (Tape Automated Bonding) tape. The TCP type semiconductor device also includes the so-called COF (Chip On Film).
FIG. 1 is a plan view schematically showing a TCP-type semiconductor device disclosed in Japanese Patent Publication JP-2004-356339. In FIG. 1, a semiconductor chip 120 is mounted on a base film (carrier tape) 110. Moreover, a plurality of leads 130 and a plurality of contact pads 140 are formed on the base film 110. The plurality of leads 130 electrically connect between the semiconductor chip 120 and the plurality of contact pads 140, respectively.
More specifically, as shown in FIG. 1, solder resist SR is so formed as to partially cover each lead 130. The solder resist SR is resin applied on the lead 130 and plays roles of not only electrically isolating the leads 130 but also relaxing chemical stress such as corrosion and physical stress on the leads 130 due to external force. The lead 130 in a region where the solder resist SR is not formed serves as a terminal that is electrically connectable to the outside, and the region is a terminal region. The semiconductor chip 120 is mounted on a central terminal region in which the solder resist SR is not formed, and then it is resin-sealed. On the other hand, an outside terminal region in which the solder resist SR is not formed is an external terminal region and is electrically connected to the contact pads 140.
The contact pads 140 are test terminals used at the time of testing the semiconductor device and are placed within a predetermined region (pad placement region RP) on the base film 110. That is, at the time of testing the semiconductor device, the probes of the probe card come in contact with the contact pads 140 within the pad placement region RP. Then, a test signal is supplied to the semiconductor chip 120 and an output signal is retrieved from the semiconductor chip 120 through the contact pads 140 and the leads 130. It should be noted that the probe card used here also has the probe pattern where positions of the probe ends are distributed over a plurality of rows. Corresponding to the probe pattern, the contact pads 140 also are distributed over a plurality of rows as shown in FIG. 1.
In FIG. 1, a width direction and an extending direction of the base film 110 are x-direction and y-direction, respectively. The structure shown in FIG. 1 is formed repeatedly along the y-direction. On separating the semiconductor chip 120 one by one after the test, the base film 110 and the plurality of leads 130 are cut along a cut line CL indicated by a dashed line in FIG. 1. At this time, the contact pads 140 in the pad placement region RP remain on the base film 110.
As another related technique, a display panel is disclosed in Japanese Patent Publication JP-2008-300297A. The display panel has a panel substrate (front surface substrate) and flexible printed circuits (FPC). A plurality of first electrode terminals are arranged on one end of the panel substrate. The flexible printed circuits have a plurality of second electrode terminals that are respectively connected to the plurality of first electrode terminals. Here, the plurality of first electrode terminals are arranged in a zig-zag manner by being alternately displaced. Moreover, the plurality of second electrode terminals also are arranged in a zig-zag manner by being alternately displaced. Both of the first electrode terminal and the second electrode terminal are formed to be wide; however, the size in the width direction is different between the first electrode terminal and the second electrode terminal.
The inventor of the present application has recognized the following point. In recent years, the number of terminals of the semiconductor chip is increasing, and thus the numbers of test signals supplied to the semiconductor chip and output signals retrieved from the semiconductor chip at the time of the test also are increasing. This means increase in the number of contact pads 140 of the TCP type semiconductor device shown in FIG. 1. The increase in the number of contact pads 140 leads to enlargement of the pad placement region RP and thus to increase in the width and length of the base film 110. As a result, costs of manufacturing the TCP type semiconductor device are increased. Therefore, a technique that can reduce the costs of manufacturing the TCP type semiconductor device is desired.